1. Field of the Invention
This invention pertains to the pouch handling art and more particularly relates to an apparatus for removing air from pouches and thereafter filling the pouches with a measured quantity of substantially air-free material.
2. Description of the Prior Art
It is well known in the art to purge air and cooking gases from flexible containers or pouches having their upper ends closed, but not sealed, by moving the containers alternately through steam and water baths during processing thereby progressively forcing non-condensible gases out of the containers before sealing the containers. Wilson U.S. Pat. No. 3,501,318, which issued on Mar. 17, 1970, and is incorporated by reference herein discloses such a process.
Wilson U.S. Pat. No. 3,528,826 which issued on Sept. 15, 1970, discloses a similar system wherein closed but unsealed pouches are alternately moved into hot water and cold water troughs to first form steam within the containers and then condense the steam to progressively drive a steam-air mixture from within the container.
U.S. Pat. No. 1,920,539 which issued to White on Aug. 1, 1933, discloses a method wherein filled rigid containers, and separate caps, are passed through a steam zone at 212.degree. F. for the purpose of replacing the air in the headspace of the containers and around the caps with steam. While each cap is being sealed on a container, the container is said to be moved to a cooler zone so that the steam in the headspace condenses thereby reducing the internal pressure below atmospheric pressure.
U.S. Pat. No. 3,871,157 which issued to Domke et al. on Mar. 18, 1975, discloses a bag packaging apparatus wherein bags are severed from a film strip and are thereafter opened, filled and closed while moving through a hood that is divided into compartments. Each compartment is provided with means for independently adjusting the supply of protective gas directed into each compartment. After the bags have been closed they are moved out of the hood and are sealed while in an environment of air.
Johnson et al. U.S. Pat. No. 3,619,975 issued in the United States on Nov. 16, 1971, and discloses a pouch packaging machine which severs pouches from a strip of film at a point outside of a hood. The pouches are first opened while outside the hood with the aid of a splitting bar and a jet of gas such as nitrogen, and are thereafter advanced under a shallow hood having a non-oxidizing gas flowing therein. The pouch is thereafter again widely opened at the filling station by suction cups, is filled with an air-free product and is then advanced to a purging station. While at the purging station a tube is lowered through the product in the filled pouch and directs a non-oxidizing gas into the filled pouch to purge air therefrom. The pouch is subsequently sealed while its upper end is disposed under and aligned with a slot in the floor of the hood.